The project to aid the drought-plagued region would be at the San Vicente Reservoir, with energy storage duration of between 5-8 hours. A new, smaller reservoir would be built uphill from San Vicente, with water pumped up to it during the day and released back down at night or during peak demand periods, providing energy for a cost of next to nothing as the running water runs turbines.

The RFP, which must be responded to by 12 September 2017, requires applicants to give details of their project teams, including their qualifications to undertake such a project. San Diego Water Authority will examine proposals in autumn and winter. Negotiations with a potential full-service team should begin by the end of this year, the Water Authority said. Anyone with questions about the RFP should get them in by 29 August.